(CNN) -- He was one of the relatively few people in the world who couldn't see the picture.

President Obama's inauguration speech, shown on a cruise ship screen, was televised everywhere.

He was talking -- speaking to an enormous audience in the outdoor chill of Washington. This was less than five weeks ago, but already it feels like forever.

He raised his left arm slightly to gesture, to emphasize a point, and on an Italian-owned liner in the Caribbean Sea, somewhere below the 20th parallel, the people reclining in the warm sun by the swimming pool on the 13th deck sipped on too-early-in-the-day cocktails and played hands of cards with each other and traded jokes, and once in a while they looked up and there he was, gesturing with that left arm.

There was an enormous television screen with crystal-clear reception mounted on one of the ship's walls above the pool deck, and as Barack Obama delivered his inaugural address at the United States Capitol, he delivered it at the same moment here, on a speck in the ocean.

We were surrounded by nothing but sea in all directions, seemingly as separated from the rest of the world as people could possibly be. But there is no longer such a thing as that kind of separation.

It is both the blessing and the curse of contemporary life, and of a contemporary politician. A blessing because without this -- the constancy and immediacy and saturation reach of the electronic images, delivered live to screens tiny and huge -- someone like Obama, a member (and hardly the most powerful or renowned member) of the Illinois legislature at the beginning of 2004, would have no chance at all to be sworn in as president at the beginning of 2009.

Without the ubiquity of those electronic images, he would have lacked the vehicle by which he could introduce himself to the voters.

The curse of it -- at least for the one person every four years who is elected president -- is that there's no way to turn it off. The watching world never blinks. The face and voice of a president become so much a part of the daily lives of the rest of us that any sense of distance and reflection vanishes, evaporates.

The face and voice become a sustaining part of a long-running daily show; one appearance by the president blends into the next, one pronouncement echoes and overlaps another, and for the person at the center of it all -- the one person who isn't watching the show because he is the show -- it must at times feel as if there's no place to hide, no time to breathe.

He can try to go home, as Obama did last weekend when he returned to Chicago, but he will find that bulletins of his every move, moves that for him not so long ago were utterly routine, mundane -- a dinner out, a game of basketball, a haircut -- are relayed around the planet.

He can address a joint session of Congress, as Obama will on Tuesday night, and every paragraph, if not every sentence, will be dissected in real time by people serving as a global jury, rendering second-by-second judgments on social networking sites and cell phone text-message screens.

Almost 40 years ago, Spiro Agnew, Richard Nixon's first vice president, caused quite a stir by attacking "instant analysis" by network television commentators; his complaint was that the commentators came onto the screens as soon as the president was finished speaking and gave their own opinions of the speech, without allowing the president's words the benefit of overnight contemplation and sober consideration.

One can only imagine what Agnew would make of our political world today, in which a president's pronouncements are dissected syllable by syllable, tick-of-the-clock by tick-of-the-clock.

No person is forced to become president; the people who get there get there because they wanted the job. This is all a part of it, and the ones who run knew it -- or should have known it -- when they made the decision.

But the thing we have come to take for granted -- the ease and endlessness with which the face and voice, the very movements, of a president are delivered to even the most remote outposts of the world -- may, in the end, turn out to be a more profound development than many of the political decisions our presidents make. There is no such thing as a place too far; there is no corner into which to seek escape. For them, or for us.

Walter Winchell, the most famous journalist of his time, used to begin his Sunday evening radio broadcasts with the staccato words: "Good evening Mr. and Mrs. North and South America and all the ships at sea ... "

The imagery was of a lonely freighter out there somewhere in the dark, with Winchell's disembodied voice floating out of the blackness, like a rumor, a message in a bottle.

In 2009, Barack Obama's face on the screen in the Caribbean Sea was as sharply defined as it was at the U.S. Capitol, and some people on the pool deck slathered on sunscreen while others planned shore excursions. The president competed for their attention, as he will every day until it is someone else's turn to try.

The opinions expressed in this commentary are solely those of Bob Greene.